Identification of Risk Factors for Arrhythmia in Children and Adolescents With Hypertrophic Cardiomyopathy

Long Term Follow Up of Children and Adolescents Diagnosed With Hypertrophic Cardiomyopathy: Identification of Risk Factors That Predict Arrhythmia Events

This study will review medical information collected on children and adolescents with hypertrophic cardiomyopathy (HCM) to try to identify risk factors for arrhythmias (abnormal heart rhythms) in these patients and better guide the choice of treatment options for them. Arrhythmias arising from the ventricle (lower heart chamber) can cause dizziness, fainting or cardiac arrest. Predictors of arrhythmias in adult HCM patients may not apply to children and teenagers with HCM.

Children and adolescents 21 years of age or younger who were diagnosed with HCM and evaluated in the National Heart Lung and Blood Institute's Cardiology Branch between 1977 and 2002 may be eligible for this study.

Participants do not undergo any further testing or data gathering beyond a review of their medical records; only existing data previously collected for research purposes are used. Medical records are reviewed for age of the patient on admission to the NIH; family history of sudden death, fainting, exercise-induced low blood pressure, and results of tests on heart structure and function.

Study Overview

Status

Completed

Detailed Description

Patients with HCM have an increased incidence of sudden death, particularly younger individuals. However, HCM has markedly variable clinical presentations, and the risk of sudden death and arrhythmia events (AE) differs significantly from one patient to another. Several risk factors for AE have been proposed. These risk factors have been defined in predominantly adult HCM populations. Little data is available defining risk factors for sudden death in a carefully defined HCM population composed of only children and adolescents. Those at highest risk may benefit from implantable defibrillator (ICD) therapy. However, the universal application of ICD therapy is not without significant morbidity and mortality.

Traditional risk factors for sudden death (SD) in adult HCM patients include a family history of SD, young age, non-sustained ventricular tachycardia (VT) on Holter monitoring, increased ventricular septal thickness (ST), abnormal blood pressure (BP) response to exercise and syncope.

The purpose of this study will be to 1) to determine whether risk factors for and mechanisms of AE in adults have predictive value in children, and 2) in particular, whether ventricular septal thickness and inducible ventricular tachycardia at electrophysiologic study (EPS) would identify a subgroup of children that might benefit most from ICD implantation.

Clinical features that will be examined as potential AE predictors included: age at presentation to the NIH; family history of SD; pre-syncope or syncope; exercise-induced hypotension; ventricular septal thickness; LV outflow obstruction; elevated LV end diastolic pressure; QRS duration; QT interval; VT on ambulatory electrocardiographic monitoring; myocardial ischemia on stress nuclear perfusion imaging; inducible VT; intra-cardiac conduction intervals; and ventricular refractory periods. Statistical significance for the time-to-event analyses will be assessed using the logrank statistic for dichotomous variables and Cox's score statistic for continuous variables.

We anticipate that this study will improve risk stratification in children and adolescents with HCM, enhance our ability to predict AE, and refine guidelines for ICD therapy in children.

Study Type

Observational

Enrollment (Actual)

145

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Heart, Lung and Blood Institute (NHLBI), 9000 Rockville Pike

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

No older than 21 years (ADULT, CHILD)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

  • Children and adolescents (less than or equal to 21 years) with HCM who had been evaluated in the Cardiology Branch, National Heart Lung and Blood Institute between 1977 and 2002. HCM was diagnosed by echocardiographic demonstration of a hypertrophied non-dilated left ventricle (LV) in the absence of another cause of LV hypertrophy. All patients participated in protocols approved by the NHLBI Institutional Review Board, and provided informed written consent to participate. The patients participated in the following protocols: 98-H-0102, 77-H-0082, 99-H-0150, 01-H-0007, 96-H-0144, 94-H-0001, 84-H-0232, 98-H-0100, and 99-H-0065.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

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Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 5, 2008

Study Completion

January 25, 2012

Study Registration Dates

First Submitted

September 12, 2008

First Submitted That Met QC Criteria

September 15, 2008

First Posted (ESTIMATE)

September 16, 2008

Study Record Updates

Last Update Posted (ACTUAL)

July 2, 2017

Last Update Submitted That Met QC Criteria

June 30, 2017

Last Verified

January 25, 2012

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Hypertrophic Cardiomyopathy (HCM)

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